Inside-Outside Flow Configuration, effectively captures contaminants on the inside;Low unit-cost bags are collapsible for easy handling;Material has the ability to handle viscous fluids;Welded seams and thermally treated exterior surfaces for control of fiber migration;Manufacturing processes do not include the use of silicone or adhesives for greater purity of filtered media 3M™ Series NB Polypropylene & Polyester bag filters leverage 3M’s filtration experience and manufacturing expertise to provide cost effective solutions for applications where nominally rated bag filtration is appropriate. 3M Series NB bags are offered in Size #1 and #2 configurations in grades from 1 to 200 microns and fit into standard bag filter baskets and housings. Old 3M ID 7000122332